Variable capacity compressor



June 30, 1931- M. RIESNER 1,312,607

VARIABLE CAPACITY COMPRESSOR Original Filed Sept. 1'7 9 5 Michael ,fiics ner I ENTOR ATTORN EY Patented June 30, 1931 UNITED. STATES PATENT OFFICE 1 MICHAEL RIESNER, OF CINCINNATI, OHIO, ASSIG-NOR TO 'WOR'II-IING-TON PUMP AND- MAGHINERY CORPORATION, OF NEW.YOR-K, N.-Y., A CORPORATION" OF VIRGINIA VARIABLE CAPACITY COMPRESSOR Original application filed September 17, 192G, Serial No. 136,008. Divided and this application filed September 26, 1928.

This invention relates to means for unloading fluid compressors and broadlyto means for automatically unloading the compressor,

gradually, whenthe receiver pressure rises to predetermined degrees, and gradually loading it as the receiver pressure falls, and the .primaryobject of the invention is to provide an apparatus of thisftype which will be economical in operation, provide a relatively 1o high efiiciency compressor and one which will be relatively simple in construction and consequently cheaper to manufacture than those heretofore used.

The present invention contemplates the use in a variable capacity compressor of clearance chambers andby-pass, together with the pressure operated control apparatusto permit the gradual unloading of the compressor cylinder for permitting its operation under various predetermined percentages of its full capacity.

For a full understanding of the invention, a detailed description of the construction embodying the same in preferred form will now be given in connection with the accompanying drawing forming a part of this specifica-* tion, and which is a diagrammatic view partlyin section and partly in elevation of a vari- I able capacity compressor and its regulator or controller constructed in accordance with this invention, and features forming the invention then specifically pointed out in the claims. a

The present application is a division from my application, Serial Number 136,008,fi1ed September 17th, 1926.

Referring more particularly to the drawing, A is a compressor cylinder, B the piston and G the piston rod, which is driven in any 0 suitable manner and while no suction or discharge valves are shown in the drawing, it is to be understood that the compressors are provided with suction and discharge valves of approved type, at the crank and head ends of the cylinder A as in the construction of Serial No. 308,359.

double acting compressors of approved types.

moved in its cylinder 8 by pre-determined receiver pressure to open the valve 6 for connecting the crank end of the cylinder A with the clearance chamber 1 for unloading the crank end of the cylinder. The valve 6 is seated by a closing spring 9. h

A port 10 establishes communication between the head end of the cylinder A and the clearance chamber 2 and this port 10 is con trolled by a valve 11 which is actuated by the pressure operated piston 12. The piston 12 is operated byreceiver pressure to open the valve 11 to open the'clearance chamber 2 to the head end of the cylinder A forpartly unloading the said head end.

The port or opening 4 is controlled by a valve 14 which is actuated by a pressure operated piston 15 which is moved in its cylinder 16 by receiver pressure to openthe valve 4 for connecting the clearance chambers 1 and 2 to establish a by-pass between the crank and head ends of the cylinder'A to provide complete unloading of the cylinder at which time the compressor will operate at zero capacity.

The pistons, 7, 12 and 15 are automatically controlled by the control apparatus E which includes a piston valve 20 actuated by apparatus controlled by the receiver pressure, as is usual in such unloading devices. The receiver pressure and operation of the valve 20 is preferably secured through a pressure operated piston 21 controlled by a pilot valve 22. The pilot valve 22 is controlled by the pivoted weighted lever 23 which is in turn controlled by suitable pressure actuated mechanism of approved type, and such as shown in my c-ompanlon apphcation above referred to, and thus the pilot The clearance chambers 1 and 2 may be of any desired capacity so as to unload and load the cylinder A in the steps required, but assuming that the capacity of each clearance chamber is such as to provide one fourth unloading of the cylinder A, the operation of the construction is, as follows: assuming that the compressor is operated at full capacity,

an increase in receiver pressure above that for which the apparatus is set will operate the control apparatus and will permitfluid under pressure to pass from the pipe 24 through the cylinder 26 and pipe 27, passing from the pipe 27 through the branch pipes 28 and 29 against the inner sides of the pistons 7 and 12 forsimultaneously actuating the valves 6 and 11 and opening both the crank and the head end of the cylinder A to their respective clearance chambers 1 and 2 thus partly unloading the crank and head ends'of the cylinders so that the compressor operates at 50% capacity or other capacity depending upon the size of the clearance chambers.

On a further increase of receiver pressure, the operation of the control apparatus E is repeated and the fluid under pressure is permitted to flow from the pipe 24 through the cylinder 26 and the pipe 30 against the inner surface of the piston 15, to open the valve 14 and connect theclearance chambers 1 and 2 to form a by-pass between the crank and head ends of the cylinder so as to completely unload both ends of the cylinder, at which time the compressor operates at zero capacity.

Theloading of the compressor cylinder A is by reverse operation of the various mechanisms to the unloadingoperation; that is, npon'decrease in receiver pressure the control apparatus E operates to cut off communication between the pipe s 24 and 30 and relieves the piston of pressure, the pressure fluid bleeding from the pipe out through the cylinder 26, which permits the valve 14 to be seated and permits operation of the compressor at% capacity.

Further decrease of the receiver pressure operates the control apparatus E and cuts oil' the delivery of fluid under receiver pressure through the pipe 27 thereby relieving the pistons 7 and 12 of pressure and permitting the valves 6 and 11 to be seated, thereby permitting operation of the compressor at full or 100% capacity.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown but that these may be modified widely within the invention defined by the claims.

lVhat is claimed is:

1. In a variable capacity compressor, the combination with a cylinder, of a plurality of clearance'chambers, and pressure controlled means for partially unloading said cylinder by simultaneous opening of said clearance chambers to the cylinder, and for wholly unloading the cylinder by opening the clearance chambers to each other. 7

2. In a variable capacity compressor, the combination with a cylinder, of a clearance chamber for unloading the crank end of the cylinder, a clearance chamber for unloading the head end of the cylinder, and pressure controlled means for simultaneously opening communication between said clearance chambers and the cylinder for wholly unloading the cylinder.

3. In a variable capacity compressor, a combination with a cylinder, of'a clearance chamber for unloading the crank end of the cylinder, a clearance chamber for unloading the head end of the cylinder, and pressure controlled means for simultaneously opening communication between said clearance chambers and the cylinder for partly unloading the cylinder, said pressure controlled means further opening communication between said clearance chambers for wholly unloading the cylinder.

4. In afvariable capacity compressor, the combination with a cylinder, of a clearance chamber for unloading the crank end of said cylinder, a clearance chamber for unloading the head end of said cylinder, a partition between said clearance chambers and provided with a by-pass port to permit communication of the clearance chamberfor wholly unloading the cylinder, pressure operated valves controlling communication between the cylinder and said clearance chambers, a pressure operated valve controlling said opening for establishing communication between the clearance chambers, and pressure controlled means for operating said cylinder and clearance chamber control valves simultaneously for partial unloading of the head and crank ends of 'the'cylinder and for opening said by-pass port subsequently to the opening of the cylinder and clearance chamber valves for wholly unloading the cylinder.

5. In a variable capacity compressor, the combination with a cylinder, of a plurality of clearance chambers, and pressure controlled means for partially unloading said cylinder by simultaneous opening of said clearance chambers to the cylinder and for wholly unloading the cylinder by opening the clearance chambers to each other, said pressure controlled means being independent of the suction or discharge valves of the compressor whereby the loading and unloading of the compressor will be independent of operation of either the suction or discharge valves.

In testimony whereof I afiix my signature.

MICHAEL RIESNER. 

